Random coil phosphorus chemical shift of deoxyribonucleic acids

Random coil phosphorus chemical shift has been studied using 16 17-nucleotide DNA sequences. Due to the presence of residual base stacking in these sequences, the temperature and sequence effects were investigated at 50 and 55 degrees C. The phosphorus chemical shifts of random coil DNA sequences have been found to be independent of temperature. Sequence effect analysis shows that the phosphorus chemical shift of a nucleotide in a random coil DNA sequence depends on both its 5'- and 3'-nearest neighbors. A trimer model has been used to establish the random coil 31P chemical shift prediction protocol which shows an accuracy of 0.02 ppm.     

Bubbles in DNA by random force

We model single strand binding (SSB) proteins as agents exerting randomly oriented force on the bonds in DNA unzipping. The fluctuating force is found to unzip the double stranded DNA (dsDNA) via opening of bubbles along the chain.     

甲苯胺蓝共振光散射法测定纳克级脱氧核糖核酸

研究了吩噻嗪类染料甲苯胺蓝 (TB)与DNA作用的共振光散射光谱 ,在pH 1 0～ 1 1的范围内 ,加入DNA导致甲苯胺蓝共振光散射增强 ,在 35 0nm处 ,存在一共振光散射增强峰 ,其强度与DNA浓度呈线性关系 ,据此建立了一种测定DNA的共振光散射法。对于ctDNA ,方法的线性范围为 0～ 90 0ng·mL-1 ,检出限为6 75ng·mL-1 ,RSD为 3 7% ;对于fsDNA ,方法的线性范围为 0～ 90 0ng·mL-1 ,检出限为 2 99ng·mL-1 ,RSD为 5 6 % .已用于合成样品中DNA的测定     

荧光猝灭法研究苯乙烯氧化物与DNA的相互作用

荧光猝灭法是一种可以研究苯化合物与ＤＮＡ相互作用的动态过程的方法。研究结果表明，苯乙烯氧化物与ＤＮＡ的相互作用与苯乙烯氧化物浓度的关系服从动力学一级方程。     

Chaos game representation （CGR）-walk model for DNA sequences

Chaos game representation (CGR) is an iterative mapping technique that processes sequences of units, such as nucleotides in a DNA sequence or amino acids in a protein, in order to determine the coordinates of their positions in a continuous space. This distribution of positions has two features: one is unique, and the other is source sequence that can be recovered from the coordinates so that the distance between positions may serve as a measure of similarity between the corresponding sequences. A CGR-walk model is proposed based on CGR coordinates for the DNA sequences. The CGR coordinates are converted into a time series, and a long-memory ARFIMA (p, d, q) model, where ARFIMA stands for autoregressive fractionally integrated moving average, is introduced into the DNA sequence analysis. This model is applied to simulating real CGR-walk sequence data of ten genomic sequences. Remarkably long-range correlations are uncovered in the data, and the results from these models are reasonably fitted with those from the ARFIMA (p, d, q) model.     

斑马鱼胚胎在电离辐射生物学研究中的应用

斑马鱼胚胎最初为研究发育生物学与分子遗传学的重要模式动物,20 世纪90 年代关于斑马鱼胚胎研究的文章每年不足100 篇,到本世纪初期已上升到每年1 000 余篇,目前这个数字正呈指数增长,斑马鱼胚胎的研究范围与应用价值正也随之逐步提升。该文综述了斑马鱼胚胎在电离辐射研究领域中的应用,包括电离辐射诱导斑马鱼的毒性作用、电离辐射引起的DNA损伤及其信号转导机制,以及利用斑马鱼对辐射防护剂与增敏剂进行评价。在此基础上还特别介绍了中国科学院近代物理研究所利用斑马鱼胚胎在放射生物学研究上取得的进展,其中包括一种具有物理激发、化学刺激作用的线粒体内活性氧(ROS) 诱导剂,在非条件刺激下利用斑马鱼检测该物质的毒性,发现6 10 μL/mL 的该物质无胚胎发育毒性,然而,在一定波长的光刺激下可造成DNA双链断裂,在理论上是一种潜在的辐射增敏剂。Zebrafish embryo is a classic animal model to study developmental and molecular biology. The relatedworks using zebrafish embryo arise from less than 100 papers per year in 90 s to more than 1 000 papers per year at the beginning of 21st century. The research scope and application value of zebrafish embryo in biology studies are gradually extending, along with the exponential increase of related papers. Here, the applications of zebrafish embryo in the field of radiation biology are reviewed, including radiation-induced toxicity, signal transduction in response to radiation-induced DNA damage, and the assessment of radio-protection and radiosensitizers, respectively. The progress in radiation biology employing zebrafish embryo in Institute of Modern Physics has also been reported, includinga novel mitochondrial reactive oxygen species inducer, which can be triggered by exogenous physical signal and exert chemical stimulation. This inducer shows no obvious embryo toxicity to zebrafish under 10 μL/mL. It can induce DNA double strand breaks if activated by certain wavelength of lights. Itisa potential radiosensitizerin theory.     

席夫碱稀土配合物与DNA的作用方式

以糠醛和对氨基苯磺酸反应合成席夫碱配体,与稀土离子配位制得相应的稀土配合物,并运用光谱法研究配合物与DNA之间的作用机制,为新型抗癌药物的设计开发提供依据。采用元素分析、红外和紫外光谱对配合物性质进行表征测试,确定其化学组成为REL(OH),RE为La~(3+)、Nd~(3+)、Eu~(3+),L为去质子形式的希夫碱配体。此外,运用光谱法和循环伏安法研究了REL(OH)配合物与鲱鱼精DNA之间的作用方式。配合物在加入DNA后,特征吸收峰强度发生明显的减色效应,但峰位红移不明显。配合物能够猝灭中性红-DNA体系的荧光。Fe(CN)_6~(3-)/~(4-)的氧化还原峰电流在配合物加入后减小,式量电位有正移趋势,表明配合物、Fe(CN)_6~(3-)/~(4-)与DNA的作用存在竞争。研究结果表明:这3种席夫碱稀土配合物与鲱鱼精DNA的作用均属于嵌插,且含有不同稀土离子的配合物与DNA的作用强弱不同,作用大小次序为Eu配合物La配合物Nd配合物席夫碱,这可能与DNA和配合物中的稀土离子所发生的作用有关。     

LaPO_4∶Ce,Tb纳米荧光粉末的合成及其在指纹无损显现中的应用

采用溶剂热法在水和乙二醇的混合溶剂中合成出了高质量的LaPO_4∶Ce,Tb纳米荧光粉末。然后通过透射电子显微镜(TEM)、粉末X射线衍射(XRD)、荧光光谱(FS)等表征手段分别对稀土纳米荧光粉末的微观形貌、晶体类型、荧光性能进行了表征,合成纳米荧光粉末的形貌为单分散的纳米棒,平均长度为700nm、平均直径为20nm,其晶体结构为单斜LaPO_4晶型,并且在254nm紫外光照射下能够产生较强的绿色荧光。最后将合成的纳米荧光粉末应用于光滑客体表面汗潜指纹的无损显现中,并详细考察了指纹显现的对比度、灵敏度、选择性、背景干扰等指标。实验结果表明,使用LaPO_4∶Ce,Tb纳米荧光粉末显现的指纹在254nm紫外光的激发下能够产生明亮的绿色荧光,指纹乳突纹线部位连贯清晰、细微特征反映明显,指纹与客体之间的对比反差强烈、客体产生的背景干扰较小,因此该显现方法具有较高的对比度、灵敏度和选择性。本显现方法具有操作方法简单、显现效果优良、适用范围广泛等优点。本研究的重要创新之处在于,经LaPO_4∶Ce,Tb纳米荧光粉末显现后的指纹还可以进行后续的DNA提取及检测,这是传统的指纹显现粉末所不能及的。本研究为指纹物证和生物物证这两大物证的同时利用提供了有益参考。     

生物分子拉曼散射测定过程中荧光背景的抑制

拉曼共焦技术、表面拉曼增强技术以及降低入射激光强度的方法，被运用于SOD、DNA等生物分子拉曼散身实验中，以抑制其荧光背景，改善光谱质量。     

碱蓝6B共振光散射法检测DNA

研究了碱蓝 6B与脱氧核糖核酸在酸性条件下共振光散射特征 ,考察了影响因素和最佳反应条件 ,建立了一种测定纳克级DNA的方法。在四硼酸钠 盐酸 (pH =2 90 )缓冲溶液中 ,线性范围为 10～ 10 0 4 μg·L- 1 ,相关系数为 0 9913,检出限为 4 2 μg·L- 1 ,用于合成样品的测定结果令人满意。